The present invention relates to a coupling mechanism for a railcar moving vehicle of the type having road wheels for traveling on road, and rail wheels for traveling on rail, the vehicle being adapted to push or pull one or more railcars along a track when operating on rail. Such railcar moving vehicles typically couple to a railcar to be moved along a track, and they lift the railcar a limited amount to transfer a portion of the weight of the railcar to the railcar moving vehicle to improve the traction of the latter.
The coupling mechanism of the present invention is designed to couple with European-type railway cars having an end sill at each end of the car which supports a centrally disposed draft hook and a pair of buffers mounted one at each end of the end sill. Such a coupling operation involves moving the railcar moving vehicle to a position adjacent to one end of the railcar, engaging buffer plates on the railcar moving vehicle against telescoping cylindrical buffer members on the railcar, causing a hook on the railcar moving vehicle to be engaged with a hook on the railcar, raising the coupling mechanism on the railcar moving vehicle causing lifting forks on the coupling mechanism to partially lift the railcar to transfer a portion of the weight thereof to the railcar moving vehicle, and pulling the railcar moving vehicle hook to pull the railcar up against the railcar moving vehicle causing some compression of the two buffers, after which the railcar moving vehicle may push or pull the railcar and other railcars coupled thereto along the track.
The present invention is an improvement over a coupling mechanism described in White U.S. Pat. No. 3,232,241. The foregoing White patent discloses several embodiments of a coupling mechanism for use on a railcar moving vehicle to couple with a European-type railcar.
In one embodiment shown in FIG. 2 of the White '241 patent, the railcar includes buffers 83 and 84, but the coupling mechanism does not engage against those buffers for the purpose of pushing the railcar. Instead, pushing is achieved through a pair of seat members shown at 39 and 40 in FIG. 2 which engage against the railcar end sill as shown in FIG. 5 to both lift the railcar for weight transfer purposes, and to push the railcar. Additional lifting of the railcar to transfer weight to the railcar moving vehicle is achieved by a pair of lift hooks shown at 66 and 69 in FIG. 3 of the White '241 patent. The lift hooks 66 and 69 lift under the buffer cylinders shown at 86 and 92 in FIG. 3, although those cylinders are of limited strength and not well adapted to permit substantial lifting forces.
In order to permit coupling of the railcar moving vehicle to the railcar for purposes of pulling the latter, FIG. 2 of the White '241 patent shows a hook 101 which is movable vertically so it can be lifted and then laid over in engagement with a draft hook 79 on the railcar, after which a cylinder 98 is used to pull the hook 101 thereby pulling the railcar moving vehicle into firm engagement with the railcar. In the embodiment being described, the end portions 44 of seat members 40 are engaged firmly against the end sill 45 as shown in FIG. 5.
A further feature of the embodiment in FIGS. 1-5 of the White '241 patent involves a double pivot arrangement shown in FIG. 4. The lower square beam 30 carries the seat members 39 and 40 which effect pushing and lifting of the railcar end sill as previously described, whereas the upper beam 52 carries the two lifting hooks shown at 66 and 69 in FIG. 3. It will be seen from FIG. 4 that the lower beam 30 is pivotally mounted about a vertical axis, and the upper beam 52 is similarly pivotal about vertical pin 54. In addition, the rear ends of arms 18 and 50, which carry the beams 30 and 52 at their outer ends, are pivotal about a vertical pivot pin 21. Thus, the arms 18 and 50 are pivotal at their rear ends about vertical pivot pin 21, and the beams 30 and 52 are pivotal about vertical pivot pins at the forward ends of the arms 18 and 50. Such a double pivot arrangement has caused problems when pushing or pulling a railcar around a curve as the structure will tend to buckle or to pivot excessively under certain conditions.
One object of the present invention is to eliminate the need for lifting the buffer cylinders in order to transfer weight to the railcar moving vehicle.
Another object of the present invention is to eliminate pushing against the railcar end sill, but rather to push against the railcar buffers while applying only lifting forces to the railcar end sill.
A further one of our objects is to eliminate the double pivot arrangement disclosed in the White '241 patent.
FIG. 11 of White U.S. Pat. No. 3,232,241 is believed to be the closest prior art to the present invention. In that embodiment, a rigid casting 150 carries a beam 145 which is pivotally mounted on the casting for movement about a central vertical axis 152. The casting 150 is laterally movable by means of rollers shown at 154. However, it is important to understand that during a pushing or pulling operation, the casting 150 is freely movable to float laterally. The lateral movement of casting 150 is controlled by a suitable hydraulic cylinder only during a coupling operation when it is necessary to align the railcar moving vehicle and its coupling mechanism with the end of a railcar to be moved.
FIG. 11 of the White '241 patent also shows pusher plates 146 and 147 on the railcar moving vehicle which engage against corresponding buffers 89" and 95" on the railcar. In addition, the White '241 patent explains at column 12, lines 23-33, that lifting of the railcar for weight transfer purposes is accomplished by pads at the opposite end of beam 145 which are adapted for engagement with the underportions of outer cylindrical members 86" and 92" of buffers 83" and 84".
One further objects of the present invention is to effect pushing of a railcar by use of pusher means engagable against the buffers of a European-type railcar. However, another object is to avoid lifting of the railcar by lifting under those same buffers members, and instead our present invention utilizes lifting forks which engage and lift beneath the end sill of a railcar.
Another important advantage of our invention is the provision of a casting member which is laterally movable on rollers and which carries on one end thereof a beam which is pivotal about a vertical axis at one end of the casting member, the beam carrying both a lifting fork and a pusher plate at each end thereof.
Still another important object of the present invention is to provide means for controlling the lateral position of the above-mentioned casting member during a pushing or pulling operation, such means including sensing means for sensing relative lateral movement between one of said pusher plates and a corresponding buffer member in engagement therewith.
The foregoing and other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings.